Fungal Genus Trichoderma Research Articles

Secretome analysis of Trichoderma atroviride T17 biocontrol of Guignardia citricarpa

The fungal species Guignardia citricarpa is an important pathogen in citriculture. Members of the fungal genus Trichoderma are recognized as biocontrol agents but studies on the interactions between both fungi are scarce. This study aimed to identify extracellular proteins secreted by Trichoderma atroviride T17 that are related to the control of G. citricarpa. Two-dimensional gel electrophoresis (2D) was used to study the patterns of proteins secreted by T. atroviride T17 in medium containing glucose (control) and in medium containing G. citricarpa GC3 inactivated mycelium. We identified 59 of the 116 spots differentially expressed (50.86%) by LC–MS/MS. Of these, we highlight the presence of glycoside hydrolases (CAZy families 3, 43, 54, 76 and 93), chitinase, mutanase, α-1,3-glucanase, α-1,2-mannosidase, carboxylic hydrolase ester, carbohydrate-binding module family 13, glucan 1,3-β-glucosidase, α-galactosidase and Neutral protease 2. These proteins are related to mycoparasitism processes, stimuli and therefore to the biological control of pathogens.The results obtained are in agreement with reports describing an increase in the secretion of proteins related to mycoparasitism and biological control and a reduction in the secretion of proteins related to the metabolism of Trichoderma species grown in the presence of the pathogen. Moreover, these results are pioneer in understanding T. atroviride interaction with G. citricarpa. For the first time, we identified potential candidate proteins that may have a role in the antagonism mechanism of G. citricarpa by T. atroviride T17. Thus our results shed a light into the molecular mechanisms that T. atroviride use to control G. citricarpa.

Host-specific transcriptomic pattern of Trichoderma virens during interaction with maize or tomato roots.

BackgroundMembers of the fungal genus Trichoderma directly antagonize soil-borne fungal pathogens, and an increasing number of species are studied for their potential in biocontrol of plant pathogens in agriculture. Some species also colonize plant roots, promoting systemic resistance. The Trichoderma-root interaction is hosted by a wide range of plant species, including monocots and dicots.ResultsTo test the hypothesis that gene expression by the fungal partner in this beneficial interaction is modulated by the plant, Trichoderma virens was co-cultured with maize or tomato in a hydroponic system allowing interaction with the roots. The transcriptomes for T. virens alone were compared with fungus-inoculated tomato or maize roots by hybridization on microarrays of 11645 unique oligonucleotides designed from the predicted protein-coding gene models. Transcript levels of 210 genes were modulated by interaction with roots. Almost all were up-regulated. Glycoside hydrolases and transporters were highly represented among transcripts induced by co-culture with roots. Of the genes up-regulated on either or both host plants, 35 differed significantly in their expression levels between maize and tomato. Ten of these were expressed higher in the fungus in co-culture with tomato roots than with maize. Average transcript levels for these genes ranged from 1.9 fold higher on tomato than on maize to 60.9 fold for the most tomato-specific gene. The other 25 host-specific transcripts were expressed more strongly in co-culture with maize than with tomato. Average transcript levels for these genes were 2.5 to 196 fold higher on maize than on tomato.ConclusionsBased on the relevant role of Trichoderma virens as a biological control agent this study provides a better knowledge of its crosstalk with plants in a host-specific manner. The differentially expressed genes encode proteins belonging to several functional classes including enzymes, transporters and small secreted proteins. Among them, glycoside hydrolases and transporters are highlighted by their abundance and suggest an important factor in the metabolism of host cell walls during colonization of the outer root layers. Host-specific gene expression may contribute to the ability of T. virens to colonize the roots of a wide range of plant species.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-014-1208-3) contains supplementary material, which is available to authorized users.

Sm2, a paralog of the Trichoderma cerato-platanin elicitor Sm1, is also highly important for plant protection conferred by the fungal-root interaction of Trichoderma with maize

BackgroundThe proteins Sm1 and Sm2 from the biocontrol fungus Trichoderma virens belong to the cerato-platanin protein family. Members of this family are small, secreted proteins that are abundantly produced by filamentous fungi with all types of life-styles. Some species of the fungal genus Trichoderma are considered as biocontrol fungi because they are mycoparasites and are also able to directly interact with plants, thereby stimulating plant defense responses. It was previously shown that the cerato-platanin protein Sm1 from T. virens - and to a lesser extent its homologue Epl1 from Trichoderma atroviride - induce plant defense responses. The plant protection potential of other members of the cerato-platanin protein family in Trichoderma, however, has not yet been investigated.ResultsIn order to analyze the function of the cerato-platanin protein Sm2, sm1 and sm2 knockout strains were generated and characterized. The effect of the lack of Sm1 and Sm2 in T. virens on inducing systemic resistance in maize seedlings, challenged with the plant pathogen Cochliobolus heterostrophus, was tested. These plant experiments were also performed with T. atroviride epl1 and epl2 knockout strains. In our plant-pathogen system T. virens was a more effective plant protectant than T. atroviride and the results with both Trichoderma species showed concordantly that the level of plant protection was more strongly reduced in plants treated with the sm2/epl2 knockout strains than with sm1/epl1 knockout strains.ConclusionsAlthough the cerato-platanin genes sm1/epl1 are more abundantly expressed than sm2/epl2 during fungal growth, Sm2/Epl2 are, interestingly, more important than Sm1/Epl1 for the promotion of plant protection conferred by Trichoderma in the maize-C. heterostrophus pathosystem.Electronic supplementary materialThe online version of this article (doi:10.1186/s12866-014-0333-0) contains supplementary material, which is available to authorized users.

Wheat takeall lessons learned during a search for effective biological control

Takeall (causal agent Gaeumannomyces graminis var tritici) is one of the most important soilborne diseases of wheat Greenhouse screening of microorganisms for disease suppression was conducted using a targeted approach that focused on the fungal genus Trichoderma In spite of indications of disease suppression in preliminary assays effective biocontrol was not observed in subsequent tests Explanations for this apparent loss of disease suppression could include insufficient numbers of potential biocontrol agents screened during the selection process or the issue of falsepositive (type 1 error) results

Designing a SCAR molecular marker for monitoring Trichoderma cf. harzianum in experimental communities.

Several species of the fungal genus Trichoderma establish biological interactions with various micro- and macro-organisms. Some of these interactions are relevant in ecological terms and in biotechnological applications, such as biocontrol, where Trichoderma could be considered as an invasive species that colonizes a recipient community. The success of this invasion depends on multiple factors, which can be assayed using experimental communities as study models. Therefore, the aim of this work is to develop a species-specific sequence-characterized amplified region (SCAR) marker to monitor the colonization and growth of T. cf. harzianum when it invades experimental communities. For this study, 16 randomly amplified polymorphic DNA (RAPD) primers of 10-mer were used to generate polymorphic patterns, one of which generated a band present only in strains of T. cf. harzianum. This band was cloned, sequenced, and five primers of 20-23 mer were designed. Primer pairs 2F2/2R2 and 2F2/2R3 successfully and specifically amplified fragments of 278 and 448 bp from the T. cf. harzianum BpT10a strain DNA, respectively. Both primer pairs were also tested against the DNA from 14 strains of T. cf. harzianum and several strains of different fungal genera as specificity controls. Only the DNA from the strains of T. cf. harzianum was successfully amplified. Moreover, primer pair 2F2/2R2 was assessed by quantitative real-time polymerase chain reaction (PCR) using fungal DNA mixtures and DNA extracted from fungal experimental communities as templates. T. cf. harzianum was detectable even when as few as 100 copies of the SCAR marker were available or even when its population represented only 0.1% of the whole community.

The transcription factor Ste12 mediates the regulatory role of the Tmk1 MAP kinase in mycoparasitism and vegetative hyphal fusion in the filamentous fungus Trichoderma atroviride.

Mycoparasitic species of the fungal genus Trichoderma are potent antagonists able to combat plant pathogenic fungi by direct parasitism. An essential step in this mycoparasitic fungus-fungus interaction is the detection of the fungal host followed by activation of molecular weapons in the mycoparasite by host-derived signals. The Trichoderma atroviride MAP kinase Tmk1, a homolog of yeast Fus3/Kss1, plays an essential role in regulating the mycoparasitic host attack, aerial hyphae formation and conidiation. However, the transcription factors acting downstream of Tmk1 are hitherto unknown. Here we analyzed the functions of the T. atroviride Ste12 transcription factor whose orthologue in yeast is targeted by the Fus3 and Kss1 MAP kinases. Deletion of the ste12 gene in T. atroviride not only resulted in reduced mycoparasitic overgrowth and lysis of host fungi but also led to loss of hyphal avoidance in the colony periphery and a severe reduction in conidial anastomosis tube formation and vegetative hyphal fusion events. The transcription of several orthologues of Neurospora crassa hyphal fusion genes was reduced upon ste12 deletion; however, the Δste12 mutant showed enhanced expression of mycoparasitism-relevant chitinolytic and proteolytic enzymes and of the cell wall integrity MAP kinase Tmk2. Based on the comparative analyses of Δste12 and Δtmk1 mutants, an essential role of the Ste12 transcriptional regulator in mediating outcomes of the Tmk1 MAPK pathway such as regulation of the mycoparasitic activity, hyphal fusion and carbon source-dependent vegetative growth is suggested. Aerial hyphae formation and conidiation, in contrast, were found to be independent of Ste12.

The Polyketide Synthase Gene pks4 of Trichoderma reesei Provides Pigmentation and Stress Resistance

Species of the fungal genus Trichoderma (Hypocreales, Ascomycota) are well-known for their production of various secondary metabolites. Nonribosomal peptides and polyketides represent a major portion of these products. In a recent phylogenomic investigation of Trichoderma polyketide synthase (PKS)-encoding genes, the pks4 from T. reesei was shown to be an orthologue of pigment-forming PKSs involved in synthesis of aurofusarin and bikaverin in Fusarium spp. In this study, we show that deletion of this gene in T. reesei results in loss of green conidial pigmentation and in pigmentation alteration of teleomorph structures. It also has an impact on conidial cell wall stability and the antagonistic abilities of T. reesei against other fungi, including formation of inhibitory metabolites. In addition, deletion of pks4 significantly influences the expression of other PKS-encoding genes of T. reesei. To our knowledge, this is the first indication that a low-molecular-weight pigment-forming PKS is involved in defense, mechanical stability, and stress resistance in fungi.

EVOLUTION OF HABITAT PREFERENCE AND NUTRITION MODE IN A COSMOPOLITAN FUNGAL GENUS WITH EVIDENCE OF INTERKINGDOM HOST JUMPS AND MAJOR SHIFTS IN ECOLOGY

Host jumps by microbial symbionts are often associated with bursts of species diversification driven by the exploitation of new adaptive zones. The objective of this study was to infer the evolution of habitat preference (decaying plants, soil, living fungi, and living plants), and nutrition mode (saprotrophy and mycoparasitism) in the fungal genus Trichoderma to elucidate possible interkingdom host jumps and shifts in ecology. Host and ecological role shifts were inferred by phylogenetic analyses and ancestral character reconstructions. The results support several interkingdom host jumps and also show that the preference for a particular habitat was gained or lost multiple times. Diversification analysis revealed that mycoparasitism is associated with accelerated speciation rates, which then suggests that this trait may be linked to the high number of species in Trichoderma. In this study it was also possible to infer the cryptic roles that endophytes or soil inhabitants play in their hosts by evaluating their closest relatives and determining their most recent ancestors. Findings from this study may have implications for understanding certain evolutionary processes such as species radiations in some hyperdiverse groups of fungi, and for more applied fields such as the discovery and development of novel biological control strategies.

Comparative analysis of the repertoire of G protein-coupled receptors of three species of the fungal genus Trichoderma

BackgroundEukaryotic organisms employ cell surface receptors such as the seven-transmembrane G protein-coupled receptors (GPCRs) as sensors to connect to the environment. GPCRs react to a variety of extracellular cues and are considered to play central roles in the signal transduction in fungi. Several species of the filamentous ascomycete Trichoderma are potent mycoparasites, i.e. can attack and parasitize other fungi, which turns them into successful bio-fungicides for the protection of plants against fungal phytopathogens. The identification and characterization of GPCRs will provide insights into how Trichoderma communicates with its environment and senses the presence of host fungi.ResultsWe mined the recently published genomes of the two mycoparasitic biocontrol agents Trichoderma atroviride and Trichoderma virens and compared the identified GPCR-like proteins to those of the saprophyte Trichoderma reesei. Phylogenetic analyses resulted in 14 classes and revealed differences not only among the three Trichoderma species but also between Trichoderma and other fungi. The class comprising proteins of the PAQR family was significantly expanded both in Trichoderma compared to other fungi as well as in the two mycoparasites compared to T. reesei. Expression analysis of the PAQR-encoding genes of the three Trichoderma species revealed that all except one were actually transcribed. Furthermore, the class of receptors with a DUF300 domain was expanded in T. atroviride, and T. virens showed an expansion of PTH11-like receptors compared to T. atroviride and T. reesei.ConclusionsComparative genome analyses of three Trichoderma species revealed a great diversity of putative GPCRs with genus- and species- specific differences. The expansion of certain classes in the mycoparasites T. atroviride and T. virens is likely to reflect the capability of these fungi to establish various ecological niches and interactions with other organisms such as fungi and plants. These GPCRs consequently represent interesting candidates for future research on the mechanisms underlying mycoparasitism and biocontrol.

Generation of Trichoderma atroviride mutants with constitutively activated G protein signaling by using geneticin resistance as selection marker

BackgroundSpecies of the fungal genus Trichoderma are important industrial producers of cellulases and hemicellulases, but also widely used as biocontrol agents (BCAs) in agriculture. In the latter function Trichoderma species stimulate plant growth, induce plant defense and directly antagonize plant pathogenic fungi through their mycoparasitic capabilities. The recent release of the genome sequences of four mycoparasitic Trichoderma species now forms the basis for large-scale genetic manipulations of these important BCAs. Thus far, only a limited number of dominant selection markers, including Hygromycin B resistance (hph) and the acetamidase-encoding amdS gene, have been available for transformation of Trichoderma spp. For more extensive functional genomics studies the utilization of additional dominant markers will be essential.ResultsWe established the Escherichia coli neomycin phosphotransferase II-encoding nptII gene as a novel selectable marker for the transformation of Trichoderma atroviride conferring geneticin resistance. The nptII marker cassette was stably integrated into the fungal genome and transformants exhibited unaltered phenotypes compared to the wild-type. Co-transformation of T. atroviride with nptII and a constitutively activated version of the Gα subunit-encoding tga3 gene (tga3Q207L) resulted in a high number of mitotically stable, geneticin-resistant transformants. Further analyses revealed a co-transformation frequency of 68% with 15 transformants having additionally integrated tga3Q207L into their genome. Constitutive activation of the Tga3-mediated signaling pathway resulted in increased vegetative growth and an enhanced ability to antagonize plant pathogenic host fungi.ConclusionThe neomycin phosphotransferase II-encoding nptII gene from Escherichia coli proved to be a valuable tool for conferring geneticin resistance to the filamentous fungus T. atroviride thereby contributing to an enhanced genetic tractability of these important BCAs.

20‐Residue and 11‐residue peptaibols from the fungus Trichoderma longibrachiatum are synergistic in forming Na+/K+‐permeable channels and adverse action towards mammalian cells

Certain species of the filamentous fungal genus Trichoderma (e.g. Trichoderma longibrachiatum and Trichoderma citrinoviride) are among the emerging clinical pathogens and also the most common species in the indoor space of mould-damaged buildings. The molecules involved in its pathology are not known. In the present study, we report that 0.5-2.6 wt% of the T. longibrachiatum mycelial biomass consisted of thermostable secondary metabolites mitochondriotoxic to mammalian cells. These were identified by LC/MS as one 11-residue and eight 20-residue peptaibols, AcAib-Asn-Leu/Ile-Leu/Ile-Aib-Pro-Leu/Ile-Leu/Ile-Aib-Pro-Leuol/Ileol (1175 Da) and AcAib-Ala-Aib-Ala-Aib-Ala/Aib-Gln-Aib-Val/Iva-Aib-Gly-Leu/Ile-Aib-Pro-Val/Iva-Aib-Val/Iva/Aib-Gln/Glu-Gln-Pheol(1936-1965 Da) (Aib, α-aminoisobutyric acid; Ac, acetyl; Ileol, isoleucinol; Iva, isovaline; Leuol, leucinol; Pheol, phenylalaninol). The toxic effects on boar sperm cells depended on these peptaibols, named trilongins. The trilongins formed voltage dependent, Na(+)/K(+) permeable channels in biomembranes. The permeability ratios for Na(+) ions, relative to K(+), of the 11-residue trilongin channel (0.95 : 1) and the 20-residue trilongin channel (0.8 : 1) were higher than those of alamethicin. The combined 11-residue and 20-residue trilongins generated channels that remained in an open state for a longer time than those formed by either one of the peptaibols alone. Corresponding synergy was observed in toxicokinetics. With 11-residue and 20-residue trilongins combined 1 : 2 w/w, an effective median concentration (EC(50) ) of 0.6 μg·mL(-1) was reached within 30 min, and the EC(50) shifted down to 0.2 μg·mL(-1) upon extended exposure. By contrast, with 11-residue or 20-residue trilonging separately in 30 min of exposure, the EC(50) values were 15 and 3 μg·mL(-1) , respectively, and shifted down to 1.5 and 0.4 μg·mL(-1) upon extended exposure. This is the first report on ion-channel forming peptaibols with synergistic toxicity from T. longibrachiatum strains isolated from clinical samples.

Biocontrol genes from Trichoderma species: A review

Accepted 25 November, 2011 In the world, the traditional agricultural practices are getting affected by various problems such as disease, pest, drought, decreased soil fertility due to use of hazardous chemical pesticides, pollution and global warming. As a result, there is a need for some eco-friendly biocontrol agents that help in resolving the previous mentioned problems. The various types of biological control agents such as bacteria and fungi are involved in biocontrol activity. Among them, fungal genus Trichoderma plays a major role in controlling the plant diseases. The species of Trichoderma are known to produce different kinds of enzymes which have a significant role in biocontrol activity like cell wall degradation, biotic and abiotic stress tolerance, hyphal growth, antagonistic activity against plant pathogens. By the advance techniques laid in the molecular biology, we can easily isolate, characterize, clone, sequence and express the functions of these genes and can study their functions and role in the biocontrol mechanism. This review article explains about the role, and functions of some major biocontrol genes present in the Trichoderma species viz., Trichoderma harzianum , Trichoderma viride , Trichoderma atroviride , Trichoderma reesei , Trichoderma hamatum and Trichoderma longibrachiatum .

Comparative molecular evolution of trichoderma chitinases in response to mycoparasitic interactions.

Certain species of the fungal genus Trichoderma are potent mycoparasites and are used for biological control of fungal diseases on agricultural crops. In Trichoderma, whole-genome sequencing reveal between 20 and 36 different genes encoding chitinases, hydrolytic enzymes that are involved in the mycoparasitic attack. Sequences of Trichoderma chitinase genes chi18-5, chi18-13, chi18-15 and chi18-17, which all exhibit specific expression during mycoparasitism-related conditions, were determined from up to 13 different taxa and studied with regard to their evolutionary patterns. Two of them, chi18-13 and chi18-17, are members of the B1/B2 chitinase subgroup that have expanded significantly in paralog number in mycoparasitic Hypocrea atroviridis and H. virens. Chi18-13 contains two codons that evolve under positive selection and seven groups of co-evolving sites. Chi18-15 displays a unique codon-usage and contains five codons that evolve under positive selection and three groups of co-evolving sites. Regions of high amino acid variability are preferentially localized to substrate- or product side of the catalytic clefts. Differences in amino acid diversity/conservation patterns between different Trichoderma clades are observed. These observations show that Trichoderma chitinases chi18-13 and chi18-15 evolve in a manner consistent with rapid co-evolutionary interactions and identifies putative target regions involved in determining substrate-specificity.

Transcriptomic response of the mycoparasitic fungus Trichoderma atroviride to the presence of a fungal prey

BackgroundCombating the action of plant pathogenic microorganisms by mycoparasitic fungi has been announced as an attractive biological alternative to the use of chemical fungicides since two decades. The fungal genus Trichoderma includes a high number of taxa which are able to recognize, combat and finally besiege and kill their prey. Only fragments of the biochemical processes related to this ability have been uncovered so far, however.ResultsWe analyzed genome-wide gene expression changes during the begin of physical contact between Trichoderma atroviride and two plant pathogens Botrytis cinerea and Rhizoctonia solani, and compared with gene expression patterns of mycelial and conidiating cultures, respectively. About 3000 ESTs, representing about 900 genes, were obtained from each of these three growth conditions. 66 genes, represented by 442 ESTs, were specifically and significantly overexpressed during onset of mycoparasitism, and the expression of a subset thereof was verified by expression analysis. The upregulated genes comprised 18 KOG groups, but were most abundant from the groups representing posttranslational processing, and amino acid metabolism, and included components of the stress response, reaction to nitrogen shortage, signal transduction and lipid catabolism. Metabolic network analysis confirmed the upregulation of the genes for amino acid biosynthesis and of those involved in the catabolism of lipids and aminosugars.ConclusionThe analysis of the genes overexpressed during the onset of mycoparasitism in T. atroviride has revealed that the fungus reacts to this condition with several previously undetected physiological reactions. These data enable a new and more comprehensive interpretation of the physiology of mycoparasitism, and will aid in the selection of traits for improvement of biocontrol strains by recombinant techniques.

Control of the bean rust fungus Uromyces appendiculatus by means of Trichoderma harzianum: leaf disc assays on the antibiotic effect of spore suspensions and culture filtrates

Several species of the fungal genus Trichoderma act as antagonists of other fungi. A number of strains from the Trichoderma species T. harzianum Rifai are used as biological control agents for the control of soilborne as well as foliar plant pathogens. Six T. harzianum strains, five of them isolated from commercial preparations, were evaluated for their capability to control the bean rust fungus Uromyces appendiculatus (Pers. ex Pers.) Unger. Different kinds of leaf disc assays were performed with conidial spore suspensions and sterile culture filtrates of the T. harzianum strains. Great differences were observed concerning the efficacy of the Trichoderma strains to reduce the number of the uredial pustules developing after rust inoculation which followed the application of the particular Trichoderma strains. Efficacy values ranged from 1 to over 50%. Increasing spore or culture filtrate concentrations of the two most effective isolates T12 and TU led to decreases in the number of developing uredial pustules. Culture filtrate applications had a protective but no curative effect. T12 spore suspensions maintained their disease reducing activity even when autoclaved. This and some other evidence for an antibiotic interaction between T. harzianum and U. appendiculatus are discussed.

Quantitative real-time PCR effectively detects and quantifies colonization of sclerotia of Sclerotinia sclerotiorum by Trichoderma spp.

Some members of the fungal genus Trichoderma are able to colonize and destroy sclerotia, the thick-walled resting structures of the soilborne plant pathogenic fungus Sclerotinia sclerotiorum, thus providing a potential means of biological disease control. However, current methods to detect and quantify colonization of sclerotia are labor-intensive, and generally qualitative rather than quantitative in nature. Our objective was to develop quantitative real-time PCR (polymerase chain reaction) methods to detect and measure colonization of sclerotia by Trichoderma spp. Specific PCR primer/probe sets were developed for Trichoderma spp. and for S. sclerotiorum. A total of 180 ITS1 (internal transcribed spacer) and ITS2 sequences from different species in the genus Trichoderma were aligned, and consensus sequences were determined. Six candidate primer sets were based on conserved regions of the consensus sequence, and the specificity of each nucleotide sequence was examined using BLAST (Basic Local Alignment Search Tool; NCBI) software. Each candidate primer set was tested on genomic DNA of T. harzianum strain ThzID1-M3, as well as six different Trichoderma isolates from soil, and on genomic DNA of S. sclerotiorum. The optimum primer/probe set selected, TGP4, successfully amplified genomic DNA of all Trichoderma isolates tested, and showed high precision and reproducibility over a linear range of eight orders of magnitude, from 85 ng to 8.5 fg of T. harzianum genomic DNA. TGP4 did not amplify S. sclerotiorum DNA. A specific PCR primer/probe set (TMSCL2) was developed for S. sclerotiorum, based on the calmodulin gene sequence. TMSCL2 did not amplify Trichoderma DNA. Quantitative real-time PCR with the primers then was evaluated in experiments to test differential effects of two soil moisture levels (−50 kPa, −1000 kPa matric potential) on biocontrol of S. sclerotiorum by indigenous Trichoderma spp. Periodically over 40 days, Trichoderma and S. sclerotiorum DNA in sclerotia were quantified by PCR with appropriate primers. Over 90% of the sclerotia were colonized by indigenous Trichoderma spp. at −1000 kPa, over the 40-day period, compared to only 60% at −50 kPa. In addition to determining incidence of colonization, the PCR method allowed measurement of the extent of sclerotial colonization, which also was significantly greater in the drier soil. Quantitative real-time PCR with the TGP4 primer/probe set provides a sensitive detection and measurement tool to evaluate colonization of sclerotia by Trichoderma spp.

Facts and Challenges in the Understanding of the Biosynthesis of Peptaibols by Trichoderma

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Facts and Challenges in the Understanding of the Biosynthesis of Peptaibols by Trichoderma

Species of the mitosporic filamentous fungal genus Trichoderma are prominent producers of both short (7-11 residues) and long (18-20 residues) peptaibols and peptaibiotics, which are thought to be involved in their interaction with other living systems. Numerous reviews are available regarding biodiversity, structure, and mode of action of these peptide derivatives, but little emphasis has been paid to the physiology and genetics of their formation. In this review article, we used the recent knowledge on biosynthesis and production of these components to speculate on some of the unknown points. We also highlight areas where further research is most urgently needed.

Two new species of Trichoderma from Yunnan, China

Two new species of the fungal genus Trichoderma, Trichoderma compactum and Trichoderma yunnanense, isolated from rhizosphere of tobacco in Yunnan Province, China are described based on morphological characters and phylogenetic analyses of nucleotide sequences. Our DNA sequences included the internal transcribed spacer (ITS) regions of the rDNA cluster (ITS1 and ITS2), and partial sequences of the translation elongation factor 1-alpha (tef1) and a fragment of the gene coding for endochitinase 42 (ech42). The analyses show that T. compactum belongs to the Harzianum clade, and T. yunnanense belongs to the Hamatum clade.

Peptaibols of Trichoderma

The fungal genus Trichoderma has various applications in industry and in medicine, and several species have economic importance as sources of enzymes, antibiotics, plant growth promoters, decomposers of xenobiotics, and as commercial biofungicides. Peptaibiotics and peptaibols are a class of linear peptides synthesized by such fungi, and more than 300 have been described to date. Of this class, those compounds exhibiting antimicrobial activity are referred to as antibiotic peptides. In this review, the biosynthesis, fermentation, structure elucidation (by MS and NMR techniques in particular) and biological activity of antibiotic peptides from Trichoderma species are described.